<svg width="100%" height="100%" preserveAspectRatio="none" 
     xmlns="http://www.w3.org/2000/svg"
     xmlns:xlink="http://www.w3.org/1999/xlink">
 
  <title>Testcase for scaled filter with non-integer x and y and objectBoundingBox</title> 
  <defs>
    <filter id="filter" filterUnits="objectBoundingBox" x="0.5" y="0.5" width="0.25" height="0.25">
      <feFlood flood-color="red" width="1" height="1" />
    </filter>
  </defs>

  <rect width="100%" height="100%" fill="lime"/>
  <g transform="scale(400)">
    <rect width="1" height="1" filter="url(#filter)" />
  </g>
  <rect x="200" y="200" width="100" height="100" fill="lime" />

</svg>
